In any electrochemical reaction, the driving force, i.e., the voltage, is greater than the theoretically necessary voltage and the additional amount of voltage required is known as the overvoltage. Many methods have been used in the past to reduce overvoltage including the use of depolarizers and various structural devices. The problem, however, is complicated because there is an overvoltage associated with each of the gases liberated during the electrochemical reaction.
There are numerous electrochemical processes in which the electrolyte contains halogen ion, particularly chlorine ions, and in which chlorine is generated during the reaction so that there is a chlorine overvoltage associated with the electrochemical cell.
The use of carbon electrodes, i.e., electrodes manufactured of carbon, graphite, activated graphite, and the like, is desirable because of a combination of their relatively low cost and availability. Unfortunately, such carbon electrodes have a significant chlorine overvoltage.
It is accordingly the object of this invention to provide a means for considerably and permanently decreasing the oxidation and reduction chlorine overvoltages of such carbon electrodes. This and other objects of the invention will become apparent to those skilled in the art from the following detailed description.